The present invention refers to data communication systems. In particular, to a data communication system with a plurality of switching units and communication links forming a network having at least one loop, whereby the network is logically divided in at least two virtual sub-networks, each forming a spanning tree. More particularly, the present invention refers to a interconnecting network structure in an Ethernet environment.
Ethernet is turning out to be the preferred networking technology for recent deployments of Metropolitan Area Networks and Cluster networks. Economies of scale, ease of service provisioning, high bandwidth, ease of interconnection with LANs, and scalability are some of the prominent reasons for this preferential status of Ethernets.
Though Ethernet is a preferred technology for metro and cluster networks, it has certain serious shortcomings. Primarily, the spanning tree based switching mechanism in Ethernets utilizes at most N−1 links in a network of N switches. This limited utilization produces an imbalance of load which is impractical in MAN and cluster networks from a performance perspective.
Sharma et al.: “Viking: A Multi-Spanning-Tree Ethernet Architecture for Metropolitan Area and Cluster Networks”, IEEE INFOCOM 2004, presents a system called ‘Viking’ addressing the aforementioned issues. The core idea of the Viking system is to use multiple spanning trees in conjunction with VLAN technology to maximize the overall throughput performance of the network by utilizing multiple redundant links. Further, Viking provides fault tolerant features by providing a mechanism to divert the affected communication over to alternate paths after detecting failures. In effect, Viking strives to provide a fault-tolerant traffic engineering solution for Metro Ethernets and Cluster Networks. Viking relies on Virtual LAN technology for selection of appropriate switching paths. VLANs are conventionally used to simplify network administration, reduce cost of segregation, and improve security. Viking deviates from this conventional paradigm and uses tag based VLANs to select the desired switching path between a pair of end-hosts. All paths which can possibly be used as switching paths are absorbed in different spanning trees. Since each spanning tree instance corresponds to a particular VLAN, explicit selection of a VLAN results in an implicit selection of the switching path associated with the corresponding spanning tree. In case of failures, the end-hosts merely need to change the VLAN id in subsequent frames to select an alternate switching path. Each of the end-hosts needs to run a Viking Node Controller (VNC) module which is responsible for VLAN selection during network operation.
Object of the present invention is to provide a data communication system with improved applicability in different computing environments.